usql update

usql is still very primitive..it just barely works

debug.lsp

@@ -1,6 +1,19 @@
-(usql "create table data (ticker varchar(8), price float null)")
-(usql "load data from '/Users/vaclavt/Library/Mobile Documents/com~apple~CloudDocs/Development/usql/data.csv')")
-(print (usql "select ticker, price from data"))
+(define create_tbl_sql "create table prices (datetime integer, symbol varchar(8), prev_close float, open float, price float, change float, change_prct varchar(16))")
+(define insert_sql "insert into prices (datetime, symbol, prev_close, open, price, change, change_prct) values (1626979443, 'MPC', 54.08, 53.82, 53.63, -0.832101, '-0.83 %')")
+(define select_sql "select to_string(datetime, '%d.%m.%Y %H:%M:%S'), symbol, prev_close, open, price, change, change_prct from prices")
+
+
+(print (usql create_tbl_sql))
+(print (usql insert_sql))
+(print (usql select_sql))
+
+(print (usql "select to_string(datetime, '%d.%m.%Y %H:%M:%S'), symbol, prev_close, open, price, change, change_prct values from prices"))
+
+
+
+;; (print (usql "create table data (ticker varchar(8), price float null)"))
+;; (usql "load data from '/Users/vaclavt/Library/Mobile Documents/com~apple~CloudDocs/Development/usql/data.csv')")
+;; (print (usql "select ticker, price from data"))
 
 ;; (read-url "https://api.nasdaq.com/api/calendar/dividends/")
 

ml.cpp

@@ -1926,14 +1926,12 @@ MlValue throw_exception(std::vector<MlValue> args, MlEnvironment &env) {
 }
 
 MlValue usql(std::vector<MlValue> args, MlEnvironment &env) {
+	eval_args(args, env);
+
 	if (args.size() != 1)
 		throw MlError(MlValue("usql", throw_exception), env, args.size() > 1 ? TOO_MANY_ARGS : TOO_FEW_ARGS);
 
-	try {
-		return uSQL::instance().execute(args[0].as_string());
-	} catch (std::exception &e) {
-		return MlValue::nil();
-	}
+	return uSQL::instance().execute(args[0].as_string());
 }
 
 }	// namespace builtin

ml_usql.cpp

@@ -19,11 +19,11 @@ MlValue uSQL::ivaluize(const usql::Table *table) {
 			auto c = row.ithColumn(i);
 			auto type = table->m_col_defs[i].type;
 			if (type == ColumnType::integer_type) {
-				columns.push_back(MlValue((long)c->integerValue()));
+				columns.push_back(MlValue(c->getIntValue()));
 			} else if (type == ColumnType::float_type) {
-				columns.push_back(MlValue((double)c->floatValue()));
+				columns.push_back(MlValue(c->getDoubleValue()));
 			} else {
-				columns.push_back(MlValue::string(c->stringValue()));
+				columns.push_back(MlValue::string(c->getStringValue()));
 			}
 		}
 		rows.push_back(columns);

usql/CMakeLists.txt

@@ -0,0 +1,21 @@
+cmake_minimum_required(VERSION 3.0)
+
+set(CMAKE_CXX_STANDARD          17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_CXX_EXTENSIONS        OFF)
+
+set(CMAKE_OSX_DEPLOYMENT_TARGET "10.14")
+
+
+project(usql)
+
+set(PROJECT_NAME usql)
+
+set(SOURCE
+	exception.cpp lexer.cpp parser.cpp usql.cpp main.cpp table.cpp table.h row.cpp row.h csvreader.cpp csvreader.h ml_date.cpp)
+
+add_executable(${PROJECT_NAME} ${SOURCE})
+
+target_link_libraries(${PROJECT_NAME} stdc++ m)
+
+target_compile_options(usql PRIVATE -g)

usql/Radme.md

@@ -1,11 +0,0 @@
-
-### TODO
-- unify using of float and double keywords to double
-- use long data type for int
-- add exceptions
-- class members should have prefix m_
-- add pipe | token
-- add to_date a to_number functions
-- add min and max functions
-- add logging
-- add const wherever should be

usql/Readme.md

@@ -0,0 +1,11 @@
+
+### TODO
+- save table command
+- move csv generation from usql(save_table) to table class
+- add exceptions
+- class members should have prefix m_
+- add pipe | token
+- add to_date a to_string functions
+- add min and max functions, eg aggregate functions
+- add logging
+- add const wherever should be

usql/clib/date.h

@@ -0,0 +1 @@
+../../clib/date.h

usql/data.csv

@@ -0,0 +1,3 @@
+Ticker,Price
+FDX,257.3
+C,59.85

usql/exception.cpp

@@ -2,7 +2,7 @@
 
 namespace usql {
 
-Exception::Exception(const std::string &msg) {
+Exception::Exception(const std::string &msg) : std::runtime_error(msg) {
 	cause = msg;
 }
 

usql/exception.h

@@ -6,7 +6,7 @@
 
 namespace usql {
 
-class Exception : public std::exception {
+class Exception : public std::runtime_error {
 private:
     std::string cause;
 

usql/lexer.cpp

@@ -13,12 +13,12 @@ namespace usql {
 
     Lexer::Lexer() {
     	k_words_regex =
-    		    "[0-9]+\\.[0-9]+|[0-9][0-9_]+[0-9]|[0-9]+|[A-Za-z]+[A-Za-z0-9_#]*|[\\(\\)\\[\\]\\{\\}]|[-\\+\\*/"
+    		    "[-+]?[0-9]+\\.[0-9]+|[-+]?[0-9][0-9_]+[0-9]|[0-9]+|[A-Za-z]+[A-Za-z0-9_#]*|[\\(\\)\\[\\]\\{\\}]|[-\\+\\*/"
 			",;:\?]|==|>=|<=|~=|>|<|=|;|~|\\||or|and|\n|\r|\r\n|'([^']|'')*'|\".*?\"|%.*?\n";
-	    k_int_regex = "[0-9]+";
-	    k_int_underscored_regex = "[0-9][0-9_]+[0-9]";
-	    k_double_regex = "[0-9]+\\.[0-9]+";
-	    k_identifier_regex = "[A-Za-z]+[A-Za-z0-9_#]*";
+    	k_int_regex = "[-+]?[0-9]+";
+	k_int_underscored_regex = "[-+]?[0-9][0-9_]+[0-9]";
+	k_double_regex = "[-+]?[0-9]+\\.[0-9]+";
+	k_identifier_regex = "[A-Za-z]+[A-Za-z0-9_#]*";
     }
 
     void Lexer::parse(const std::string &code) {
@@ -156,6 +156,9 @@ namespace usql {
 	    if (token == "<=")
 		    return TokenType::lesser_equal;
 
+	    if (token == "as")
+		    return TokenType::keyword_as;
+
 	    if (token == "create")
 		    return TokenType::keyword_create;
 
@@ -195,6 +198,9 @@ namespace usql {
 	    if (token == "load")
 		    return TokenType::keyword_load;
 
+	    if (token == "save")
+		    return TokenType::keyword_save;
+
 	    if (token == "not")
 		    return TokenType::keyword_not;
 
@@ -202,7 +208,7 @@ namespace usql {
 		    return TokenType::keyword_null;
 
 	    if (token == "integer")
-		    return TokenType::keyword_int;
+		    return TokenType::keyword_integer;
 
 	    if (token == "float")
 		    return TokenType::keyword_float;
@@ -326,6 +332,9 @@ namespace usql {
 		    case TokenType::lesser_equal:
 			    txt = "<=";
 			    break;
+		    case TokenType::keyword_as:
+			    txt = "as";
+			    break;
 		    case TokenType::keyword_create:
 			    txt = "create";
 			    break;
@@ -356,13 +365,16 @@ namespace usql {
 		    case TokenType::keyword_load:
 			    txt = "load";
 			    break;
+		    case TokenType::keyword_save:
+			    txt = "save";
+			    break;
 		    case TokenType::keyword_not:
 			    txt = "not";
 			    break;
 		    case TokenType::keyword_null:
 			    txt = "null";
 			    break;
-		    case TokenType::keyword_int:
+		    case TokenType::keyword_integer:
 			    txt = "integer";
 			    break;
 		    case TokenType::keyword_float:

usql/lexer.h

@@ -20,12 +20,14 @@ namespace usql {
 	greater_equal,
 	lesser,
 	lesser_equal,
+	keyword_as,
 	keyword_create,
 	keyword_table,
 	keyword_where,
 	keyword_delete,
 	keyword_update,
 	keyword_load,
+	keyword_save,
 	keyword_from,
 	keyword_insert,
 	keyword_into,
@@ -35,7 +37,7 @@ namespace usql {
 	keyword_copy,
 	keyword_not,
 	keyword_null,
-	keyword_int,
+	keyword_integer,
 	keyword_float,
 	keyword_varchar,
 	int_number,

usql/main.cpp

@@ -0,0 +1,52 @@
+#include "parser.h"
+#include "usql.h"
+
+// https://dev.to/joaoh82/what-would-sqlite-look-like-if-written-in-rust-part-1-2np4
+
+// parser should get m_lexer as param and table executor to be able translate * or get types or so
+// podporovat create as select
+// drop table
+
+int main(int argc, char *argv[]) {
+	std::vector<std::string> sql_commands{
+		    "create table a (i integer not null, s varchar(64), f float null)",
+		    "insert into a (i, s) values(1, upper('one'))",
+		    "insert into a (i, s) values(2, 'two')",
+		    "insert into a (i, s) values(3, 'two')",
+		    "insert into a (i, s) values(4, lower('FOUR'))",
+		    "insert into a (i, s) values(5, 'five')",
+		    "insert into a (i, s) values(to_date('20.12.1973', '%d.%m.%Y'), 'six')",
+		    "save table a into '/tmp/a.csv'",
+		    "select i, s from a where i > 2",
+		    "select i, s from a where i = 1",
+		    "select i, s from a where s = 'two'",
+		    "select i, s from a where i <= 3 and s = 'one'",
+		    "select i, s from a where i > 0",
+		    "delete from a where i = 4",
+		    "select i, s from a where i > 0",
+		    "update a set f = 9.99 where i = 3",
+		    "select i, s, f from a where i = 3",
+		    "update a set s = 'three', f = f + 0.01 where i = 3",
+		    "select i, s, f from a where i = 3",
+		    "create table data (ticker varchar(8), price float null)",
+		    "load data from '/Users/vaclavt/Library/Mobile Documents/com~apple~CloudDocs/Development/usql/data.csv')",
+		    "select ticker, price from data",
+		    "select i, s, f from a where i < 300",
+		    "create table x as select i, s, f from a where i < 300",
+		    "select i, s, f from x where i < 300",
+		    "select i, s, f from a where i > 300",
+		    "select i, to_string(i, '%d.%m.%Y'), s, f from a where i > 300"
+	};
+
+
+	usql::USql uSql{};
+
+	for (auto command : sql_commands) {
+		std::cout << command << std::endl;
+		auto result = uSql.execute(command);
+
+		result->print();
+	}
+
+	return 0;
+}

usql/ml_date.cpp

@@ -0,0 +1,59 @@
+
+#include "ml_date.h"
+
+long now() {
+	// get-universal-time
+	time_t t = std::time(0);
+	long int now = static_cast<long int>(t);
+
+	return now;
+}
+
+std::string date_to_string(const long datetime, const std::string format) {
+	// std::locale::global(std::locale("en-US.UTF8"));
+
+	time_t timestamp = datetime;
+	char mbstr[128];
+
+	if (std::strftime(mbstr, sizeof(mbstr), format.c_str(), std::localtime(&timestamp))) {
+		std::string result = {mbstr};
+		return result;
+	}
+	// TODO exception here
+    return "invalid argument";
+}
+
+long string_to_date(const std::string &datestr, const std::string &format) {
+	// format for example "%d.%m.%Y";
+
+	std::istringstream in{datestr.c_str()};
+	date::sys_seconds tp;
+	in >> date::parse(format, tp);
+	return tp.time_since_epoch().count();
+}
+
+long add_to_date(const long datetime, const long quantity, const std::string &part) {
+	// part is one of 'year', 'month', 'day', 'hour', 'minute' or 'second'
+
+	// very basic implementation, just for now - no timezones DST etc
+	time_t base = datetime;
+	struct tm *tm = localtime(&base);
+
+	if (part == "year") {
+		tm->tm_year += quantity;
+	} else if (part == "month") {
+		tm->tm_mon += quantity;
+	} else if (part == "day") {
+		tm->tm_mday += quantity;
+	} else if (part == "hour") {
+		tm->tm_hour += quantity;
+	} else if (part == "minute") {
+		tm->tm_min += quantity;
+	} else if (part == "second") {
+		tm->tm_sec += quantity;
+	} else {
+		// TODO exception here
+	}
+
+	return mktime(tm);
+}

usql/ml_date.h

@@ -0,0 +1,17 @@
+
+#pragma once
+
+#include "clib/date.h"
+
+#include <string>
+#include <vector>
+
+
+long now();
+
+std::string date_to_string(const long datetime, const std::string format);
+
+long string_to_date(const std::string &datestr, const std::string &format);
+
+long add_to_date(const long datetime, const long quantity, const std::string &part);
+

usql/parser.cpp

@@ -6,158 +6,218 @@ namespace usql {
 // TOOD handle premature eof
 
     Parser::Parser() {
-	    lexer = Lexer{};
+	    m_lexer = Lexer{};
     }
 
     std::unique_ptr<Node> Parser::parse(const std::string &code) {
-	    lexer.parse(code);
-	    // lexer.debugTokens();
+	    m_lexer.parse(code);
+	    // m_lexer.debugTokens();
 
-	    if (lexer.tokenType() == TokenType::keyword_create && lexer.nextTokenType() == TokenType::keyword_table) {
+	    if (m_lexer.tokenType() == TokenType::keyword_create && m_lexer.nextTokenType() == TokenType::keyword_table) {
 		    return parse_create_table();
 	    }
-	    if (lexer.tokenType() == TokenType::keyword_insert) {
+	    if (m_lexer.tokenType() == TokenType::keyword_insert) {
 		    return parse_insert_into_table();
 	    }
-	    if (lexer.tokenType() == TokenType::keyword_select) {
+	    if (m_lexer.tokenType() == TokenType::keyword_select) {
 		    return parse_select_from_table();
 	    }
-	    if (lexer.tokenType() == TokenType::keyword_delete) {
+	    if (m_lexer.tokenType() == TokenType::keyword_delete) {
 		    return parse_delete_from_table();
 	    }
-	    if (lexer.tokenType() == TokenType::keyword_update) {
+	    if (m_lexer.tokenType() == TokenType::keyword_update) {
 		    return parse_update_table();
 	    }
-	    if (lexer.tokenType() == TokenType::keyword_load) {
+	    if (m_lexer.tokenType() == TokenType::keyword_load) {
 		    return parse_load_table();
 	    }
+	    if (m_lexer.tokenType() == TokenType::keyword_save) {
+		    return parse_save_table();
+	    }
 
-	    std::cout << "ERROR, token:" << lexer.currentToken().token_string << std::endl;
+	    std::cout << "ERROR, token:" << m_lexer.currentToken().token_string << std::endl;
 	    return std::make_unique<Node>(NodeType::error);
     }
 
     std::unique_ptr<Node> Parser::parse_create_table() {
 	    std::vector<ColDefNode> cols_def{};
 
-	    lexer.skipToken(TokenType::keyword_create);
-	    lexer.skipToken(TokenType::keyword_table);
+	    m_lexer.skipToken(TokenType::keyword_create);
+	    m_lexer.skipToken(TokenType::keyword_table);
 
-	    if (lexer.tokenType() != TokenType::identifier) { /* TODO handle error */ }
-	    std::string table_name = lexer.consumeCurrentToken().token_string;
+	    if (m_lexer.tokenType() != TokenType::identifier) { /* TODO handle error */ }
+	    std::string table_name = m_lexer.consumeCurrentToken().token_string;
 
-	    lexer.skipToken(TokenType::open_paren);
-	    int column_order = 0;
-	    do {
-		    std::string column_name;
-		    ColumnType column_type;
-		    int column_len{1};
-		    bool column_nullable{true};
+	    // create as select
+	    if (m_lexer.tokenType() == TokenType::keyword_as) {
+		m_lexer.skipToken(TokenType::keyword_as);
 
-		    // column name
-		    if (lexer.tokenType() != TokenType::identifier) { /* TODO handle error */ }
-		    column_name = lexer.consumeCurrentToken().token_string;
+		std::unique_ptr<Node> select = parse_select_from_table();
 
-		    // column type and optionally len
-		    if (lexer.tokenType() == TokenType::keyword_int) {
-			    column_type = ColumnType::integer_type;
-			    lexer.nextToken();
-		    } else if (lexer.tokenType() == TokenType::keyword_float) {
-			    column_type = ColumnType::float_type;
-			    lexer.nextToken();
-		    } else if (lexer.tokenType() == TokenType::keyword_varchar) {
-			    column_type = ColumnType::varchar_type;
-			    lexer.nextToken();
-			    lexer.skipToken(TokenType::open_paren);
-			    if (lexer.tokenType() == TokenType::int_number) {
-				    column_len = std::stoi(lexer.consumeCurrentToken().token_string);
-			    } else { /* TODO handle error */ }
-			    lexer.skipToken(TokenType::close_paren);
-		    } else { /* TODO handle error */ }
+		return  std::make_unique<CreateTableAsSelectNode>(table_name, std::move(select));
+	    } else {
+	    	m_lexer.skipToken(TokenType::open_paren);
+	    	int column_order = 0;
+	    	do {
+	    		std::string column_name;
+	    		ColumnType column_type;
+	    		int column_len{1};
+	    		bool column_nullable{true};
 
-		    if (lexer.tokenType() == TokenType::keyword_not) {
-			    lexer.nextToken();
-			    lexer.skipToken(TokenType::keyword_null);
-			    column_nullable = false;
-		    } else if (lexer.tokenType() == TokenType::keyword_null) {
-			    lexer.nextToken();
-		    }
+	    		// column name
+	    		if (m_lexer.tokenType() != TokenType::identifier) {
+				throw Exception("syntax error, expected identifier");
+			}
+	    		column_name = m_lexer.consumeCurrentToken().token_string;
 
-		    cols_def.push_back(
-				ColDefNode(column_name, column_type, column_order++, column_len, column_nullable));
+	    		// column type and optionally len
+	    		if (m_lexer.tokenType() == TokenType::keyword_integer) {
+	    			column_type = ColumnType::integer_type;
+	    			m_lexer.nextToken();
+	    		} else if (m_lexer.tokenType() == TokenType::keyword_float) {
+	    			column_type = ColumnType::float_type;
+	    			m_lexer.nextToken();
+	    		} else if (m_lexer.tokenType() == TokenType::keyword_varchar) {
+	    			column_type = ColumnType::varchar_type;
+	    			m_lexer.nextToken();
+	    			m_lexer.skipToken(TokenType::open_paren);
+	    			if (m_lexer.tokenType() == TokenType::int_number) {
+	    				column_len = std::stoi(m_lexer.consumeCurrentToken().token_string);
+	    			} else {
+					throw Exception("syntax error, expected int number");
+				}
+	    			m_lexer.skipToken(TokenType::close_paren);
+	    		} else {
+				throw Exception("syntax error, column type expected");
+			}
 
-		    lexer.skipTokenOptional(TokenType::comma);
+	    		if (m_lexer.tokenType() == TokenType::keyword_not) {
+	    			m_lexer.nextToken();
+	    			m_lexer.skipToken(TokenType::keyword_null);
+	    			column_nullable = false;
+	    		} else if (m_lexer.tokenType() == TokenType::keyword_null) {
+	    			m_lexer.nextToken();
+	    		}
 
-		    // TODO in future constraints
+	    		cols_def.push_back( ColDefNode(column_name, column_type, column_order++, column_len, column_nullable));
 
-	    } while (lexer.tokenType() != TokenType::close_paren);
+	    		m_lexer.skipTokenOptional(TokenType::comma);
 
+	    		// TODO in future constraints
+	    	} while (m_lexer.tokenType() != TokenType::close_paren);
 
-	    return std::make_unique<CreateTableNode>(table_name, cols_def);
+	    	return std::make_unique<CreateTableNode>(table_name, cols_def);
+	    }
     }
 
 
     std::unique_ptr<Node> Parser::parse_insert_into_table() {
-	    std::vector<Node> exec_code{};
-	    std::vector<ColNameNode> cols_names{};
-	    std::vector<ColValueNode> cols_values{};
+	    std::vector<ColNameNode> column_names{};
+	    std::vector<std::unique_ptr<Node>> column_values{};
 
-	    lexer.skipToken(TokenType::keyword_insert);
-	    lexer.skipToken(TokenType::keyword_into);
+	    m_lexer.skipToken(TokenType::keyword_insert);
+	    m_lexer.skipToken(TokenType::keyword_into);
 
 	    // table name
-	    if (lexer.tokenType() != TokenType::identifier) { /* TODO handle error */ }
-	    std::string table_name = lexer.consumeCurrentToken().token_string;
+	    if (m_lexer.tokenType() != TokenType::identifier) { /* TODO handle error */ }
+	    std::string table_name = m_lexer.consumeCurrentToken().token_string;
 
 	    // column names
-	    lexer.skipToken(TokenType::open_paren);
+	    m_lexer.skipToken(TokenType::open_paren);
 	    do {
-		    if (lexer.tokenType() != TokenType::identifier) { /* TODO handle error */ }
-		    cols_names.push_back(lexer.consumeCurrentToken().token_string);
+		    if (m_lexer.tokenType() != TokenType::identifier) { /* TODO handle error */ }
+		    column_names.push_back(m_lexer.consumeCurrentToken().token_string);
 
-		    lexer.skipTokenOptional(TokenType::comma);
-	    } while (lexer.tokenType() != TokenType::close_paren);
-	    lexer.skipToken(TokenType::close_paren);
+		    m_lexer.skipTokenOptional(TokenType::comma);
+	    } while (m_lexer.tokenType() != TokenType::close_paren);
+	    m_lexer.skipToken(TokenType::close_paren);
 
-	    lexer.skipToken(TokenType::keyword_values);
+	    m_lexer.skipToken(TokenType::keyword_values);
 
 	    // column values
-	    lexer.skipToken(TokenType::open_paren);
+	    m_lexer.skipToken(TokenType::open_paren);
 	    do {
-		    cols_values.push_back(lexer.consumeCurrentToken().token_string);
+		    auto col_value =  parse_value();
+		    column_values.push_back(std::move(col_value));
 
-		    lexer.skipTokenOptional(TokenType::comma);
-	    } while (lexer.tokenType() != TokenType::close_paren);
-	    lexer.skipToken(TokenType::close_paren);
+		    m_lexer.skipTokenOptional(TokenType::comma);
+	    } while (m_lexer.tokenType() != TokenType::close_paren);
+	    m_lexer.skipToken(TokenType::close_paren);
 
-	    return std::make_unique<InsertIntoTableNode>(table_name, cols_names, cols_values);
+	    return std::make_unique<InsertIntoTableNode>(table_name, column_names, std::move(column_values));
     }
 
-    std::unique_ptr<Node> Parser::parse_select_from_table() {
-	    std::vector<ColNameNode> cols_names{};
+std::unique_ptr<Node> Parser::parse_value() {
+	if (m_lexer.tokenType() == TokenType::int_number) {
+		return std::make_unique<IntValueNode>(std::stoi(m_lexer.consumeCurrentToken().token_string));
+	}
+	if (m_lexer.tokenType() == TokenType::double_number) {
+		return std::make_unique<DoubleValueNode>(std::stof(m_lexer.consumeCurrentToken().token_string));
+	}
+	if (m_lexer.tokenType() == TokenType::string_literal) {
+		return std::make_unique<StringValueNode>(m_lexer.consumeCurrentToken().token_string);
+	}
+	if (m_lexer.tokenType() == TokenType::identifier && m_lexer.nextTokenType() == TokenType::open_paren) {
+		// function
+		std::string function_name = m_lexer.consumeCurrentToken().token_string;
+		std::vector<std::unique_ptr<Node>> pars;
 
-	    lexer.skipToken(TokenType::keyword_select);
-	    while (lexer.tokenType() != TokenType::keyword_from) {
-		    cols_names.push_back(lexer.consumeCurrentToken().token_string);
-		    lexer.skipTokenOptional(TokenType::comma);
-	    }
+		m_lexer.skipToken(TokenType::open_paren);
+		while (m_lexer.tokenType() != TokenType::close_paren) {        // TODO handle errors
+			pars.push_back(parse_value());
+			m_lexer.skipTokenOptional(TokenType::comma);
+		}
+		m_lexer.skipToken(TokenType::close_paren);
+		return std::make_unique<FunctionNode>(function_name, std::move(pars));
+	}
+	if (m_lexer.tokenType() == TokenType::identifier) {
+		std::string name = m_lexer.consumeCurrentToken().token_string;
+		return std::make_unique<ColNameNode>(name);
+	}
 
-	    lexer.skipToken(TokenType::keyword_from);
-	    std::string table_name = lexer.consumeCurrentToken().token_string;
+	throw Exception("Syntax error, current token: " + m_lexer.currentToken().token_string);
+}
 
-	    std::unique_ptr<Node> where_node = parse_where_clause();
+std::unique_ptr<Node> Parser::parse_select_from_table() {
+	auto cols = std::make_unique<std::vector<SelectColNode>>();
 
-//    if (lexer.tokenType() == TokenType::keyword_order_by) {}
-//    if (lexer.tokenType() == TokenType::keyword_offset) {}
-//    if (lexer.tokenType() == TokenType::keyword_limit) {}
+	m_lexer.skipToken(TokenType::keyword_select);
 
-	    return std::make_unique<SelectFromTableNode>(table_name, cols_names, std::move(where_node));
-    }
+	int i = 1;
+	while (m_lexer.tokenType() != TokenType::keyword_from) {
+		auto column_value = parse_value();
+		std::string column_alias;
+
+		if (column_value->node_type == NodeType::column_name) {
+			column_alias = ((ColNameNode*) column_value.get())->name;
+		} else {
+			column_alias = "c" + std::to_string(i);
+			i++;
+		}
+
+		cols->push_back(SelectColNode{std::move(column_value), column_alias});
+
+		m_lexer.skipTokenOptional(TokenType::comma);
+	}
+
+	m_lexer.skipToken(TokenType::keyword_from);
+
+	std::string table_name = m_lexer.consumeCurrentToken().token_string;
+
+	std::unique_ptr<Node> where_node = parse_where_clause();
+
+//    if (m_lexer.tokenType() == TokenType::keyword_order_by) {}
+//    if (m_lexer.tokenType() == TokenType::keyword_offset) {}
+//    if (m_lexer.tokenType() == TokenType::keyword_limit) {}
+
+	return std::make_unique<SelectFromTableNode>(table_name, std::move(cols), std::move(where_node));
+}
 
     std::unique_ptr<Node> Parser::parse_delete_from_table() {
-	    lexer.skipToken(TokenType::keyword_delete);
-	    lexer.skipToken(TokenType::keyword_from);
+	    m_lexer.skipToken(TokenType::keyword_delete);
+	    m_lexer.skipToken(TokenType::keyword_from);
 
-	    std::string table_name = lexer.consumeCurrentToken().token_string;
+	    std::string table_name = m_lexer.consumeCurrentToken().token_string;
 
 	    std::unique_ptr<Node> where_node = parse_where_clause();
 
@@ -165,22 +225,22 @@ namespace usql {
     }
 
     std::unique_ptr<Node> Parser::parse_update_table() {
-	    lexer.skipToken(TokenType::keyword_update);
-	    lexer.skipTokenOptional(TokenType::keyword_table);
+	    m_lexer.skipToken(TokenType::keyword_update);
+	    m_lexer.skipTokenOptional(TokenType::keyword_table);
 
-	    std::string table_name = lexer.consumeCurrentToken().token_string;
+	    std::string table_name = m_lexer.consumeCurrentToken().token_string;
 
-	    lexer.skipToken(TokenType::keyword_set);
+	    m_lexer.skipToken(TokenType::keyword_set);
 
 	    std::vector<ColNameNode> cols_names;
 	    std::vector<std::unique_ptr<Node>> values;
 
 	    do {
-		    cols_names.push_back(lexer.consumeCurrentToken().token_string);
-		    lexer.skipToken(TokenType::equal);
+		    cols_names.push_back(m_lexer.consumeCurrentToken().token_string);
+		    m_lexer.skipToken(TokenType::equal);
 
 		    std::unique_ptr<Node> left = Parser::parse_operand_node();
-		    if (Lexer::isArithmeticalOperator(lexer.tokenType())) {
+		    if (Lexer::isArithmeticalOperator(m_lexer.tokenType())) {
 			    ArithmeticalOperatorType op = parse_arithmetical_operator();
 			    std::unique_ptr<Node> right = Parser::parse_operand_node();
 
@@ -192,9 +252,9 @@ namespace usql {
 					std::make_unique<ArithmeticalOperatorNode>(ArithmeticalOperatorType::copy_value,
 										   std::move(left), std::move(right)));
 		    }
-		    lexer.skipTokenOptional(TokenType::comma);
+		    m_lexer.skipTokenOptional(TokenType::comma);
 
-	    } while (lexer.tokenType() != TokenType::keyword_where && lexer.tokenType() != TokenType::eof);
+	    } while (m_lexer.tokenType() != TokenType::keyword_where && m_lexer.tokenType() != TokenType::eof);
 
 	    std::unique_ptr<Node> where_node = parse_where_clause();
 
@@ -202,37 +262,51 @@ namespace usql {
     }
 
     std::unique_ptr<Node> Parser::parse_load_table() {
-	    lexer.skipToken(TokenType::keyword_load);
-	    lexer.skipTokenOptional(TokenType::keyword_into);
+	    m_lexer.skipToken(TokenType::keyword_load);
+	    m_lexer.skipTokenOptional(TokenType::keyword_into);
 
-	    std::string table_name = lexer.consumeCurrentToken().token_string;
+	    std::string table_name = m_lexer.consumeCurrentToken().token_string;
 
-	    lexer.skipTokenOptional(TokenType::keyword_from);
+	    m_lexer.skipTokenOptional(TokenType::keyword_from);
 
-	    std::string file_name = lexer.consumeCurrentToken().token_string;
+	    std::string file_name = m_lexer.consumeCurrentToken().token_string;
 
 	    return std::make_unique<LoadIntoTableNode>(table_name, file_name);
     }
 
+
+    std::unique_ptr<Node> Parser::parse_save_table() {
+    	m_lexer.skipToken(TokenType::keyword_save);
+    	m_lexer.skipTokenOptional(TokenType::keyword_table);
+
+    	std::string table_name = m_lexer.consumeCurrentToken().token_string;
+
+    	m_lexer.skipTokenOptional(TokenType::keyword_into);
+
+    	std::string file_name = m_lexer.consumeCurrentToken().token_string;
+
+    	return std::make_unique<SaveTableNode>(table_name, file_name);
+    }
+
     std::unique_ptr<Node> Parser::parse_where_clause() {
 	    // TODO add support for multiple filters
 	    // TODO add support for parenthesis
 
-	    if (lexer.tokenType() != TokenType::keyword_where) {
+	    if (m_lexer.tokenType() != TokenType::keyword_where) {
 		    return std::make_unique<TrueNode>();
 	    }
 
 	    std::unique_ptr<Node> node;
-	    lexer.skipToken(TokenType::keyword_where);
+	    m_lexer.skipToken(TokenType::keyword_where);
 	    do {
 		    node = parse_relational_expression();
 
-		    if (Lexer::isLogicalOperator(lexer.tokenType())) {
+		    if (Lexer::isLogicalOperator(m_lexer.tokenType())) {
 			    auto operation = parse_logical_operator();
 			    std::unique_ptr<Node> node2 = parse_relational_expression();
 			    node = std::make_unique<LogicalOperatorNode>(operation, std::move(node), std::move(node2));
 		    }
-	    } while (lexer.tokenType() != TokenType::eof);    // until whole where clause parsed
+	    } while (m_lexer.tokenType() != TokenType::eof);    // until whole where clause parsed
 
 	    return node;
     }
@@ -247,13 +321,13 @@ namespace usql {
 
     std::unique_ptr<Node> Parser::parse_operand_node() {
 	    // while not end or order or limit
-	    auto token_type = lexer.tokenType();
-	    std::string tokenString = lexer.consumeCurrentToken().token_string;
+	    auto token_type = m_lexer.tokenType();
+	    std::string tokenString = m_lexer.consumeCurrentToken().token_string;
 	    switch (token_type) {
 		    case TokenType::int_number:
 			    return std::make_unique<IntValueNode>(std::stoi(tokenString));
 		    case TokenType::double_number:
-			    return std::make_unique<FloatValueNode>(std::stod(tokenString));
+			    return std::make_unique<DoubleValueNode>(std::stod(tokenString));
 		    case TokenType::string_literal:
 			    return std::make_unique<StringValueNode>(tokenString);
 		    case TokenType::identifier:
@@ -264,7 +338,7 @@ namespace usql {
     }
 
     RelationalOperatorType Parser::parse_relational_operator() {
-	    auto op = lexer.consumeCurrentToken();
+	    auto op = m_lexer.consumeCurrentToken();
 	    switch (op.type) {
 		    case TokenType::equal:
 			    return RelationalOperatorType::equal;
@@ -284,7 +358,7 @@ namespace usql {
     }
 
     LogicalOperatorType Parser::parse_logical_operator() {
-	    auto op = lexer.consumeCurrentToken();
+	    auto op = m_lexer.consumeCurrentToken();
 	    switch (op.type) {
 		    case TokenType::logical_and:
 			    return LogicalOperatorType::and_operator;
@@ -296,7 +370,7 @@ namespace usql {
     }
 
     ArithmeticalOperatorType Parser::parse_arithmetical_operator() {
-	    auto op = lexer.consumeCurrentToken();
+	    auto op = m_lexer.consumeCurrentToken();
 	    switch (op.type) {
 		    case TokenType::plus:
 			    return ArithmeticalOperatorType::plus_operator;

usql/parser.h

@@ -8,7 +8,6 @@
 
 namespace usql {
 
-
     enum class ColumnType {
 	integer_type,
 	float_type,
@@ -25,13 +24,16 @@ namespace usql {
 	relational_operator,
 	arithmetical_operator,
 	create_table,
+	create_table_as_select,
 	insert_into,
 	select_from,
 	delete_from,
 	update_table,
 	load_table,
+	save_table,
 	column_name,
 	column_value,
+	function,
 	column_def,
 	error
     };
@@ -45,18 +47,17 @@ namespace usql {
     struct ColNameNode : Node {
 	std::string name;
 
-	ColNameNode(const std::string col_name) :
-		    Node(NodeType::column_name), name(col_name) {}
+	ColNameNode(const std::string col_name) : Node(NodeType::column_name), name(col_name) {}
     };
 
-    struct ColValueNode : Node {
-	std::string value;
+    struct SelectColNode : Node {
+        std::unique_ptr<Node>	value;
+        std::string name;
 
-	ColValueNode(const std::string col_value) :
-		    Node(NodeType::column_value), value(col_value) {}
+        SelectColNode(std::unique_ptr<Node> column, const std::string& alias) :
+        Node(NodeType::column_name), value(std::move(column)), name(alias) {}
     };
 
-    // TODO add order in row
     struct ColDefNode : Node {
 	std::string name;
 	ColumnType type;
@@ -64,11 +65,18 @@ namespace usql {
 	int length;
 	bool null;
 
-	ColDefNode(const std::string col_name, const ColumnType col_type, int col_order, int col_len, bool nullable) :
+	ColDefNode(const std::string col_name,  ColumnType col_type, int col_order, int col_len, bool nullable) :
 		    Node(NodeType::column_def), name(col_name), type(col_type), order(col_order), length(col_len),
 		    null(nullable) {}
     };
 
+    struct FunctionNode : Node {
+        std::string		function;
+        std::vector<std::unique_ptr<Node>>	params;
+
+        FunctionNode(const std::string func_name, std::vector<std::unique_ptr<Node>> pars) :
+        Node(NodeType::function), function(func_name), params(std::move(pars)) {}
+    };
 
     struct TrueNode : Node {
 	TrueNode() : Node(NodeType::true_node) {}
@@ -77,37 +85,32 @@ namespace usql {
     struct ValueNode : Node {
 	ValueNode(NodeType type) : Node(type) {}
 
-	virtual int getIntValue() = 0;
-
+	virtual bool isNull() { return false; }
+	virtual long getIntValue() = 0;
 	virtual double getDoubleValue() = 0;
-
 	virtual std::string getStringValue() = 0;
 
 	virtual ~ValueNode() {};
     };
 
     struct IntValueNode : ValueNode {
-	int value;
+	long value;
 
-	IntValueNode(int value) : ValueNode(NodeType::int_value), value(value) {}
+	IntValueNode(long value) : ValueNode(NodeType::int_value), value(value) {}
 
-	int getIntValue() { return value; };
-
-	double getDoubleValue() { return (double) value; };
-
-	std::string getStringValue() { return std::to_string(value); }
+	long getIntValue() override { return value; };
+	double getDoubleValue() override { return (double) value; };
+	std::string getStringValue() override { return std::to_string(value); }
     };
 
-    struct FloatValueNode : ValueNode {
+    struct DoubleValueNode : ValueNode {
 	double value;
 
-	FloatValueNode(double value) : ValueNode(NodeType::float_value), value(value) {}
+	DoubleValueNode(double value) : ValueNode(NodeType::float_value), value(value) {}
 
-	int getIntValue() { return (int) value; };
-
-	double getDoubleValue() { return value; };
-
-	std::string getStringValue() { return std::to_string(value); }
+	long getIntValue() override { return (long) value; };
+	double getDoubleValue() override { return value; };
+	std::string getStringValue() override { return std::to_string(value); }
     };
 
     struct StringValueNode : ValueNode {
@@ -115,11 +118,9 @@ namespace usql {
 
 	StringValueNode(std::string value) : ValueNode(NodeType::string_value), value(value) {}
 
-	int getIntValue() { return std::stoi(value); };
-
-	double getDoubleValue() { return std::stod(value); };
-
-	std::string getStringValue() { return value; };
+	long getIntValue() override { return std::stoi(value); };
+	double getDoubleValue() override { return std::stod(value); };
+	std::string getStringValue() override { return value; };
     };
 
     struct DatabaseValueNode : Node {
@@ -181,31 +182,38 @@ namespace usql {
 		    Node(NodeType::arithmetical_operator), op(op), left(std::move(left)), right(std::move(right)) {};
     };
 
-
     struct CreateTableNode : Node {
 	std::string table_name;
 	std::vector<ColDefNode> cols_defs;
 
-	CreateTableNode(const std::string name, std::vector<ColDefNode> defs) :
+	CreateTableNode(const std::string& name, std::vector<ColDefNode> defs) :
 		    Node(NodeType::create_table), table_name(name), cols_defs(defs) {}
     };
 
     struct InsertIntoTableNode : Node {
-	std::string table_name;
-	std::vector<ColNameNode> cols_names;
-	std::vector<ColValueNode> cols_values;
+	std::string				table_name;
+	std::vector<ColNameNode>		cols_names;
+	std::vector<std::unique_ptr<Node>>	cols_values;
 
-	InsertIntoTableNode(const std::string name, std::vector<ColNameNode> names, std::vector<ColValueNode> values) :
-		    Node(NodeType::insert_into), table_name(name), cols_names(names), cols_values(values) {}
+	InsertIntoTableNode(const std::string name, std::vector<ColNameNode> names, std::vector<std::unique_ptr<Node>> values) :
+		    Node(NodeType::insert_into), table_name(name), cols_names(names), cols_values(std::move(values)) {}
     };
 
     struct SelectFromTableNode : Node {
 	std::string table_name;
-	std::vector<ColNameNode> cols_names;
+	std::unique_ptr<std::vector<SelectColNode>> cols_names;
 	std::unique_ptr<Node> where;
 
-	SelectFromTableNode(std::string name, std::vector<ColNameNode> names, std::unique_ptr<Node> where_clause) :
-		    Node(NodeType::select_from), table_name(name), cols_names(names), where(std::move(where_clause)) {}
+	SelectFromTableNode(std::string name, std::unique_ptr<std::vector<SelectColNode>> names, std::unique_ptr<Node> where_clause) :
+	Node(NodeType::select_from), table_name(name), cols_names(std::move(names)), where(std::move(where_clause)) {}
+    };
+
+    struct CreateTableAsSelectNode : Node {
+        std::string		table_name;
+        std::unique_ptr<Node>	select_table;
+
+        CreateTableAsSelectNode(const std::string name, std::unique_ptr<Node> table) :
+        Node(NodeType::create_table_as_select), table_name(name), select_table(std::move(table)) {}
     };
 
     struct UpdateTableNode : Node {
@@ -226,16 +234,22 @@ namespace usql {
 
 	LoadIntoTableNode(const std::string name, std::string file) :
 		    Node(NodeType::load_table), table_name(name), filename(file) {}
+    };
 
+    struct SaveTableNode : Node {
+        std::string table_name;
+        std::string filename;
+
+        SaveTableNode(const std::string& name, std::string file) :
+        Node(NodeType::save_table), table_name(name), filename(file) {}
     };
 
     struct DeleteFromTableNode : Node {
 	std::string table_name;
 	std::unique_ptr<Node> where;
 
-	DeleteFromTableNode(const std::string name, std::unique_ptr<Node> where_clause) :
+	DeleteFromTableNode(const std::string& name, std::unique_ptr<Node> where_clause) :
 		    Node(NodeType::delete_from), table_name(name), where(std::move(where_clause)) {}
-
     };
 
 
@@ -249,32 +263,23 @@ namespace usql {
 
     private:
 	std::unique_ptr<Node> parse_create_table();
-
 	std::unique_ptr<Node> parse_insert_into_table();
-
+	std::unique_ptr<Node> parse_value();
 	std::unique_ptr<Node> parse_select_from_table();
-
 	std::unique_ptr<Node> parse_delete_from_table();
-
 	std::unique_ptr<Node> parse_update_table();
-
 	std::unique_ptr<Node> parse_load_table();
-
+	std::unique_ptr<Node> parse_save_table();
 	std::unique_ptr<Node> parse_where_clause();
-
 	std::unique_ptr<Node> parse_operand_node();
-
 	RelationalOperatorType parse_relational_operator();
-
 	LogicalOperatorType parse_logical_operator();
-
 	ArithmeticalOperatorType parse_arithmetical_operator();
 
     private:
-	Lexer lexer;
+	Lexer m_lexer;
 
 	std::unique_ptr<Node> parse_relational_expression();
-
     };
 
 }

usql/row.cpp

@@ -19,13 +19,13 @@ namespace usql {
 
 	    for (int i = 0; i < other.m_columns.size(); i++) {
 		    if (ColIntegerValue *other_v = dynamic_cast<ColIntegerValue *>(other.m_columns[i].get())) {
-			    setColumnValue(i, other_v->integerValue());
+			    setColumnValue(i, other_v->getIntValue());
 		    }
-		    if (ColFloatValue *other_v = dynamic_cast<ColFloatValue *>(other.m_columns[i].get())) {
-			    setColumnValue(i, other_v->floatValue());
+		    if (ColDoubleValue *other_v = dynamic_cast<ColDoubleValue *>(other.m_columns[i].get())) {
+			    setColumnValue(i, other_v->getDoubleValue());
 		    }
 		    if (ColStringValue *other_v = dynamic_cast<ColStringValue *>(other.m_columns[i].get())) {
-			    setColumnValue(i, other_v->stringValue());
+			    setColumnValue(i, other_v->getStringValue());
 		    }
 	    }
     }
@@ -35,22 +35,52 @@ namespace usql {
 	    return *this;
     }
 
-    void Row::setColumnValue(int col_index, int value) {
+    void Row::setColumnNull(int col_index) {
+	m_columns[col_index] = std::make_unique<ColNullValue>();
+    }
+
+    void Row::setColumnValue(int col_index, long value) {
 	    m_columns[col_index] = std::make_unique<ColIntegerValue>(value);
     }
 
     void Row::setColumnValue(int col_index, double value) {
-	    m_columns[col_index] = std::make_unique<ColFloatValue>(value);
+	    m_columns[col_index] = std::make_unique<ColDoubleValue>(value);
     }
 
     void Row::setColumnValue(int col_index, const std::string &value) {
 	    m_columns[col_index] = std::make_unique<ColStringValue>(value);
     };
 
+    void Row::setColumnValue(ColDefNode *col_def, ColValue *col_value) {
+	    if (!col_value->isNull()) {
+    		if (col_def->type == ColumnType::integer_type)
+    			setColumnValue(col_def->order, col_value->getIntValue());
+    		else if (col_def->type == ColumnType::float_type)
+    			setColumnValue(col_def->order, col_value->getDoubleValue());
+    		else if (col_def->type == ColumnType::varchar_type)
+    			setColumnValue(col_def->order, col_value->getStringValue());
+    	} else {
+    		setColumnNull(col_def->order);
+    	}
+    }
+
+    void Row::setColumnValue(ColDefNode *col_def, ValueNode *col_value) {
+    	if (!col_value->isNull()) {
+    		if (col_def->type == ColumnType::integer_type)
+    			setColumnValue(col_def->order, col_value->getIntValue());
+    		else if (col_def->type == ColumnType::float_type)
+    			setColumnValue(col_def->order, col_value->getDoubleValue());
+    		else if (col_def->type == ColumnType::varchar_type)
+    			setColumnValue(col_def->order, col_value->getStringValue());
+    	} else {
+    		setColumnNull(col_def->order);
+    	}
+    }
+
     void Row::print() {
 	    for (int ci = 0; ci < m_columns.size(); ci++) {
 		    if (ci > 0) std::cout << ",";
-		    auto v = m_columns[ci]->stringValue();
+		    auto v = m_columns[ci]->getStringValue();
 		    std::cout << v;
 	    }
 	    std::cout << std::endl;

usql/row.h

@@ -10,67 +10,54 @@ namespace usql {
 
     struct ColValue {
 
-	virtual bool isNull() { return false; };;;;
-
-	virtual int integerValue() { throw Exception("Not supported"); };
-
-	virtual double floatValue() { throw Exception("Not supported"); };
-
-	virtual std::string stringValue() { throw Exception("Not supported"); };
+	virtual bool isNull() { return false; };
+	virtual long getIntValue() { throw Exception("Not supported"); };
+	virtual double getDoubleValue() { throw Exception("Not supported"); };
+	virtual std::string getStringValue() { throw Exception("Not supported"); };
     };
 
 
     struct ColNullValue : ColValue {
 
 	virtual bool isNull() { return true; };
-
-	virtual std::string stringValue() { return "null"; };
+	virtual std::string getStringValue() { return "null"; };
     };
 
 
     struct ColIntegerValue : ColValue {
 
-	ColIntegerValue(int value) : m_integer(value) {};
-
+	ColIntegerValue(long value) : m_integer(value) {};
 	ColIntegerValue(const ColIntegerValue &other) : m_integer(other.m_integer) {};
 
-	virtual int integerValue() { return m_integer; };
-
-	virtual double floatValue() { return (double) m_integer; };
-
-	virtual std::string stringValue() { return std::to_string(m_integer); };
+	virtual long getIntValue() { return m_integer; };
+	virtual double getDoubleValue() { return (double) m_integer; };
+	virtual std::string getStringValue() { return std::to_string(m_integer); };
 
 	int m_integer;
     };
 
 
-    struct ColFloatValue : ColValue {
+    struct ColDoubleValue : ColValue {
 
-	ColFloatValue(double value) : m_float(value) {};
+	ColDoubleValue(double value) : m_double(value) {};
+	ColDoubleValue(const ColDoubleValue &other) : m_double(other.m_double) {}
 
-	ColFloatValue(const ColFloatValue &other) : m_float(other.m_float) {}
+	virtual long getIntValue() { return (long) m_double; };
+	virtual double getDoubleValue() { return m_double; };
+	virtual std::string getStringValue() { return std::to_string(m_double); };
 
-	virtual int integerValue() { return (int) m_float; };
-
-	virtual double floatValue() { return m_float; };
-
-	virtual std::string stringValue() { return std::to_string(m_float); };
-
-	double m_float;
+	double m_double;
     };
 
 
     struct ColStringValue : ColValue {
 
 	ColStringValue(const std::string value) : m_string(value) {};
-
 	ColStringValue(const ColStringValue &other) : m_string(other.m_string) {};
 
-	virtual int integerValue() { return std::stoi(m_string); };
-
-	virtual double floatValue() { return std::stod(m_string); };
-
-	virtual std::string stringValue() { return m_string; };
+	virtual long getIntValue() { return std::stoi(m_string); };
+	virtual double getDoubleValue() { return std::stod(m_string); };
+	virtual std::string getStringValue() { return m_string; };
 
 	std::string m_string;
     };
@@ -80,22 +67,22 @@ namespace usql {
 
     public:
 	Row(int cols_count);
-
 	Row(const Row &other);
 
 	Row &operator=(Row other);
 
-	void setColumnValue(int col_index, int value);
-
+	void setColumnNull(int col_index);
+	void setColumnValue(int col_index, long value);
 	void setColumnValue(int col_index, double value);
-
 	void setColumnValue(int col_index, const std::string &value);
+	void setColumnValue(ColDefNode *col_def, ColValue *col_value);
+	void setColumnValue(ColDefNode *col_def, ValueNode *col_value);
 
 	ColValue &operator[](int i) {
 		return *m_columns[i];
 	}
 
-	ColValue *ithColumn(int i) {
+	ColValue * ithColumn(int i) const {
 		return m_columns[i].get();
 	}
 
@@ -105,4 +92,4 @@ namespace usql {
 	std::vector<std::unique_ptr<ColValue>> m_columns;
     };
 
-}
+}	// namespace

usql/table.cpp

@@ -3,45 +3,71 @@
 
 namespace usql {
 
-    Table::Table(const std::string name, const std::vector<ColDefNode> columns) {
-	    m_name = name;
-	    m_col_defs = columns;
-	    m_rows.clear();
-    }
-
-    ColDefNode Table::get_column_def(const std::string &col_name) {
-	    auto name_cmp = [col_name](ColDefNode cd) { return cd.name == col_name; };
-	    auto col_def = std::find_if(begin(m_col_defs), end(m_col_defs), name_cmp);
-	    if (col_def != std::end(m_col_defs)) {
-		    return *col_def;
-	    } else {
-		    throw Exception("column not exists (" + col_name + ")");
-	    }
-    }
-
-
-    Row Table::createEmptyRow() {
-	    return Row(columns_count());
-    }
-
-
-    void Table::print() {
-	    std::cout << "** " << m_name << " **" << std::endl;
-	    for (auto row : m_rows) {
-		    row.print();
-	    }
-    }
-
-    Table::Table(const Table &other) {
-	    m_name = other.m_name;
-	    m_col_defs = other.m_col_defs;
-	    m_rows.clear();  // row not copied now
-    }
-
-    void Table::addRow(const Row &row) {
-	    // TODO validate for not null values
-	    // todo validate for length etc
-	    m_rows.push_back(row);
-    }
-
+Table::Table(const std::string name, const std::vector<ColDefNode> columns) {
+	m_name = name;
+	m_col_defs = columns;
+	m_rows.clear();
 }
+
+ColDefNode Table::get_column_def(const std::string &col_name) {
+	auto name_cmp = [col_name](ColDefNode cd) { return cd.name == col_name; };
+	auto col_def = std::find_if(begin(m_col_defs), end(m_col_defs), name_cmp);
+	if (col_def != std::end(m_col_defs)) {
+		return *col_def;
+	} else {
+		throw Exception("column not exists (" + col_name + ")");
+	}
+}
+
+
+Row Table::createEmptyRow() {
+	return Row(columns_count());
+}
+
+
+void Table::print() {
+	std::cout << "** " << m_name << " **" << std::endl;
+	for (auto row : m_rows) {
+		row.print();
+	}
+}
+
+Table::Table(const Table &other) {
+	m_name = other.m_name;
+	m_col_defs = other.m_col_defs;
+	for(const Row& orig_row : other.m_rows) {
+		addCopyOfRow(orig_row);
+	}
+}
+
+void Table::addRow(const Row &row) {
+	// TODO validate for not null values
+	// todo validate for length etc
+	m_rows.push_back(row);
+}
+
+void Table::addCopyOfRow(const Row &row) {
+	// TODO validate for not null values
+	// todo validate for length etc
+
+	Row new_row = createEmptyRow();
+
+	for(int i = 0; i < m_col_defs.size(); i++) {
+		ColValue *ct = row.ithColumn(i);
+
+		if (ct->isNull()) {
+			new_row.setColumnNull(i);
+		} else {
+			if (m_col_defs[i].type == ColumnType::integer_type) {
+				new_row.setColumnValue(i, row.ithColumn(i)->getIntValue());
+			} else if (m_col_defs[i].type == ColumnType::float_type) {
+				new_row.setColumnValue(i, row.ithColumn(i)->getDoubleValue());
+			} else if (m_col_defs[i].type == ColumnType::varchar_type) {
+				new_row.setColumnValue(i, row.ithColumn(i)->getStringValue());
+			}
+		}
+	}
+	m_rows.push_back(row);
+}
+
+}	// namespace

usql/table.h

@@ -10,7 +10,6 @@ namespace usql {
     struct Table {
 
 	Table(const Table &other);
-
 	Table(const std::string name, const std::vector<ColDefNode> columns);
 
 	ColDefNode get_column_def(const std::string &col_name);
@@ -19,6 +18,7 @@ namespace usql {
 
 	Row createEmptyRow();   // TODO this means unnecessary copying
 	void addRow(const Row &row);
+	void addCopyOfRow(const Row &row);
 
 	void print();
 

usql/usql.cpp

@@ -1,6 +1,7 @@
 #include "usql.h"
 #include "exception.h"
 #include "csvreader.h"
+#include "ml_date.h"
 
 #include <algorithm>
 #include <fstream>
@@ -8,9 +9,14 @@
 namespace usql {
 
 std::unique_ptr<Table> USql::execute(const std::string &command) {
-	auto node = m_parser.parse(command);
+	try {
+		std::unique_ptr<Node> node = m_parser.parse(command);
+		return execute(*node);
+
+	} catch (std::exception &e) {
+		return create_stmt_result_table(-1, e.what());
+	}
 
-	return execute(*node);
 }
 
 std::unique_ptr<Table> USql::execute(Node &node) {
@@ -18,18 +24,22 @@ std::unique_ptr<Table> USql::execute(Node &node) {
 	switch (node.node_type) {
 		case NodeType::create_table:
 			return execute_create_table(static_cast<CreateTableNode &>(node));
-			case NodeType::insert_into:
-				return execute_insert_into_table(static_cast<InsertIntoTableNode &>(node));
-				case NodeType::select_from:
-					return execute_select(static_cast<SelectFromTableNode &>(node));
-					case NodeType::delete_from:
-						return execute_delete(static_cast<DeleteFromTableNode &>(node));
-						case NodeType::update_table:
-							return execute_update(static_cast<UpdateTableNode &>(node));
-							case NodeType::load_table:
-								return execute_load(static_cast<LoadIntoTableNode &>(node));
-								default:
-									return create_stmt_result_table(-1, "unknown statement");
+		case NodeType::create_table_as_select:
+			return execute_create_table_as_table(static_cast<CreateTableAsSelectNode &>(node));
+		case NodeType::insert_into:
+			return execute_insert_into_table(static_cast<InsertIntoTableNode &>(node));
+		case NodeType::select_from:
+			return execute_select(static_cast<SelectFromTableNode &>(node));
+		case NodeType::delete_from:
+			return execute_delete(static_cast<DeleteFromTableNode &>(node));
+		case NodeType::update_table:
+			return execute_update(static_cast<UpdateTableNode &>(node));
+		case NodeType::load_table:
+			return execute_load(static_cast<LoadIntoTableNode &>(node));
+		case NodeType::save_table:
+			return execute_save(static_cast<SaveTableNode &>(node));
+		default:
+			return create_stmt_result_table(-1, "unknown statement");
 	}
 }
 
@@ -43,6 +53,28 @@ std::unique_ptr<Table> USql::execute_create_table(CreateTableNode &node) {
 }
 
 
+std::unique_ptr<Table> USql::execute_create_table_as_table(CreateTableAsSelectNode &node) {
+	// TODO check table does not exists
+
+	auto select = execute_select((SelectFromTableNode &) *node.select_table);
+
+	// create table
+	Table new_table{node.table_name, select->m_col_defs};
+	m_tables.push_back(new_table);
+
+	// copy rows
+	// must be here, if rows are put into new_table, they are lost during m_tables.push_table
+	Table *table = find_table(node.table_name);
+	for( Row& orig_row : select->m_rows) {
+		table->addCopyOfRow(orig_row);
+	}
+
+	select.release();	// is it correct? hoping not to release select table here and then when releasing CreateTableAsSelectNode
+
+	return create_stmt_result_table(0, "table created");
+}
+
+
 std::unique_ptr<Table> USql::execute_insert_into_table(InsertIntoTableNode &node) {
 	// TODO check column names.size = values.size
 
@@ -55,64 +87,56 @@ std::unique_ptr<Table> USql::execute_insert_into_table(InsertIntoTableNode &node
 	// copy values
 	for (size_t i = 0; i < node.cols_names.size(); i++) {
 		ColDefNode col_def = table_def->get_column_def(node.cols_names[i].name);
+		auto col_value = evalValueNode(table_def, new_row, node.cols_values[i].get());
 
-		// TODO validate value
-
-		if (col_def.type == ColumnType::integer_type) {
-			new_row.setColumnValue(col_def.order, std::stoi(node.cols_values[i].value));
-		} else if (col_def.type == ColumnType::float_type) {
-			new_row.setColumnValue(col_def.order, std::stof(node.cols_values[i].value));
-		} else {
-			new_row.setColumnValue(col_def.order, node.cols_values[i].value);
-		}
+		new_row.setColumnValue(&col_def, col_value.get());
 	}
 
 	// append new_row
 	table_def->addRow(new_row);
 
-	return create_stmt_result_table(0, "insert succeded");
+	return create_stmt_result_table(0, "insert succeeded");
 }
 
 
 std::unique_ptr<Table> USql::execute_select(SelectFromTableNode &node) {
-	// TODO create plan for accessing rows
-
 	// find source table
 	Table *table = find_table(node.table_name);
 
+
 	// create result table
 	std::vector<ColDefNode> result_tbl_col_defs{};
 	std::vector<int> source_table_col_index{};
-	int i = 0;  // new column order
-	for (auto rc : node.cols_names) {
-		ColDefNode cdef = table->get_column_def(rc.name);
-		source_table_col_index.push_back(cdef.order);
 
-		auto col = ColDefNode(rc.name, cdef.type, i, cdef.length, cdef.null);
-		result_tbl_col_defs.push_back(col);
+	for (int i = 0; i < node.cols_names->size(); i++) {
+		auto [ src_tbl_col_index, rst_tbl_col_def ]  = getColumnDefinition(table, &node.cols_names->operator[](i), i);
 
-		i++;
+		source_table_col_index.push_back(src_tbl_col_index);
+		result_tbl_col_defs.push_back(rst_tbl_col_def);
 	}
 	auto result = std::make_unique<Table>("result", result_tbl_col_defs);
 
+
 	// execute access plan
 	for (auto row = begin(table->m_rows); row != end(table->m_rows); ++row) {
 		// eval where for row
-		if (evalWhere(node.where.get(), table, row)) {
+		if (evalWhere(node.where.get(), table, *row)) {
 			// prepare empty row
 			Row new_row = result->createEmptyRow();
 
 			// copy column values
 			for (auto idx = 0; idx < result->columns_count(); idx++) {
 				auto row_col_index = source_table_col_index[idx];
-				ColValue *col_value = row->ithColumn(row_col_index);
-				if (result_tbl_col_defs[idx].type == ColumnType::integer_type)
-					new_row.setColumnValue(idx,
-							       ((ColIntegerValue *) col_value)->integerValue());
-				if (result_tbl_col_defs[idx].type == ColumnType::float_type)
-					new_row.setColumnValue(idx, col_value->floatValue());
-				if (result_tbl_col_defs[idx].type == ColumnType::varchar_type)
-					new_row.setColumnValue(idx, col_value->stringValue());
+
+				if (row_col_index == -1) {	// TODO introduce constant here
+					auto evaluated_value = evalValueNode(table, *row, node.cols_names->operator[](idx).value.get());
+					ValueNode *col_value = evaluated_value.get();
+
+					new_row.setColumnValue(&result_tbl_col_defs[idx], col_value);
+				} else {
+					ColValue *col_value = row->ithColumn(row_col_index);
+					new_row.setColumnValue(&result_tbl_col_defs[idx], col_value);
+				}
 			}
 
 			// add row to result
@@ -123,17 +147,38 @@ std::unique_ptr<Table> USql::execute_select(SelectFromTableNode &node) {
 	return std::move(result);
 }
 
+std::tuple<int, ColDefNode> USql::getColumnDefinition(Table *table, SelectColNode *select_col_node, int col_order ) {
+	std::string new_col_name = select_col_node->name;
+
+	if (select_col_node->value->node_type == NodeType::column_name) {
+		ColDefNode src_cdef = table->get_column_def(new_col_name);
+		ColDefNode cdef = ColDefNode{new_col_name, src_cdef.type, col_order, src_cdef.length, src_cdef.null};
+		return std::make_tuple(src_cdef.order, cdef);
+
+	} else if (select_col_node->value->node_type == NodeType::function) {
+		auto node = static_cast<FunctionNode *>(select_col_node->value.get());
+
+		if (node->function == "to_string") {
+			ColDefNode cdef = ColDefNode{new_col_name, ColumnType::varchar_type, col_order, 64, true};
+			return std::make_tuple(-1, cdef);
+		} else if (node->function == "to_date") {
+			ColDefNode cdef = ColDefNode{new_col_name, ColumnType::integer_type, col_order, 1, true};
+			return std::make_tuple(-1, cdef);
+		}
+		throw Exception("Unsupported function");
+	}
+	throw Exception("Unsupported node type");
+}
+
 
 std::unique_ptr<Table> USql::execute_delete(DeleteFromTableNode &node) {
-	// TODO create plan for accessing rows
-
 	// find source table
 	Table *table = find_table(node.table_name);
 
 	// execute access plan
 	auto it = table->m_rows.begin();
 	for (; it != table->m_rows.end();) {
-		if (evalWhere(node.where.get(), table, it)) {
+		if (evalWhere(node.where.get(), table, *it)) {
 			// TODO this can be really expensive operation
 			it = table->m_rows.erase(it);
 		} else {
@@ -141,38 +186,25 @@ std::unique_ptr<Table> USql::execute_delete(DeleteFromTableNode &node) {
 		}
 	}
 
-	return create_stmt_result_table(0, "delete succeded");
+	return create_stmt_result_table(0, "delete succeeded");
 }
 
 
 std::unique_ptr<Table> USql::execute_update(UpdateTableNode &node) {
-	// TODO create plan for accessing rows
-
 	// find source table
 	Table *table = find_table(node.table_name);
 
 	// execute access plan
 	for (auto row = begin(table->m_rows); row != end(table->m_rows); ++row) {
 		// eval where for row
-		if (evalWhere(node.where.get(), table, row)) {
+		if (evalWhere(node.where.get(), table, *row)) {
 			int i = 0;
-			for (auto col : node.cols_names) {
-				// TODO cache it like in select
-				ColDefNode cdef = table->get_column_def(col.name);
+			for (const auto& col : node.cols_names) {
+				ColDefNode col_def = table->get_column_def(col.name);	// TODO cache it like in select
+				std::unique_ptr<ValueNode> new_val = evalArithmeticOperator(col_def.type,
+						      static_cast<ArithmeticalOperatorNode &>(*node.values[i]), table, *row);
 
-				std::unique_ptr<ValueNode> new_val = evalArithmetic(cdef.type,
-										    static_cast<ArithmeticalOperatorNode &>(*node.values[i]),
-										    table, row);
-
-				if (cdef.type == ColumnType::integer_type) {
-					row->setColumnValue(cdef.order, new_val->getIntValue());
-				} else if (cdef.type == ColumnType::float_type) {
-					row->setColumnValue(cdef.order, new_val->getDoubleValue());
-				} else if (cdef.type == ColumnType::varchar_type) {
-					row->setColumnValue(cdef.order, new_val->getStringValue());
-				} else {
-					throw Exception("Implement me!");
-				}
+				row->setColumnValue(&col_def, new_val.get());
 				i++;
 			}
 		}
@@ -208,7 +240,7 @@ std::unique_ptr<Table> USql::execute_load(LoadIntoTableNode &node) {
 
 			// TODO validate value
 			if (col_def.type == ColumnType::integer_type) {
-				new_row.setColumnValue(col_def.order, std::stoi(csv_line[i]));
+				new_row.setColumnValue(col_def.order, std::stol(csv_line[i]));
 			} else if (col_def.type == ColumnType::float_type) {
 				new_row.setColumnValue(col_def.order, std::stof(csv_line[i]));
 			} else {
@@ -224,154 +256,230 @@ std::unique_ptr<Table> USql::execute_load(LoadIntoTableNode &node) {
 }
 
 
-bool USql::evalWhere(Node *where, Table *table,
-		     std::vector<Row, std::allocator<Row>>::iterator &row) const {
+std::unique_ptr<Table> USql::execute_save(SaveTableNode &node) {
+	// find source table
+	Table *table_def = find_table(node.table_name);
+
+	// header
+	std::string out_string;
+	for(int i = 0; i < table_def->m_col_defs.size(); i++) {
+		if (i > 0) out_string += ",";
+		out_string += table_def->m_col_defs[i].name;
+	}
+
+	// rows
+	for (auto it = table_def->m_rows.begin() + 1; it != table_def->m_rows.end(); ++it) {
+		std::string csv_line;
+		for(int i = 0; i < table_def->m_col_defs.size(); i++) {
+			if (i > 0) csv_line += ",";
+
+			auto col = it->ithColumn(i);
+			if (!col->isNull()) {
+				csv_line += col->getStringValue();		// TODO handle enclosing commas etc
+			}
+		}
+		out_string += "\n";
+		out_string += csv_line;
+	}
+
+	// save data
+	std::ofstream file(node.filename);
+	file << out_string;
+	file.close();
+
+	return create_stmt_result_table(0, "save succeeded");
+}
+
+
+bool USql::evalWhere(Node *where, Table *table, Row &row) const {
 	switch (where->node_type) {    // no where clause
 		case NodeType::true_node:
 			return true;
-			case NodeType::relational_operator:     //  just one condition
+		case NodeType::relational_operator:     //  just one condition
 			return evalRelationalOperator(*((RelationalOperatorNode *) where), table, row);
-			case NodeType::logical_operator:
-				return evalLogicalOperator(*((LogicalOperatorNode *) where), table, row);
-				default:
-					throw Exception("Wrong node type");
+		case NodeType::logical_operator:
+			return evalLogicalOperator(*((LogicalOperatorNode *) where), table, row);
+		default:
+			throw Exception("Wrong node type");
 	}
 
 	return false;
 }
 
 
-bool USql::evalRelationalOperator(const RelationalOperatorNode &filter, Table *table,
-				  std::vector<Row, std::allocator<Row>>::iterator &row) const {
-	std::unique_ptr<ValueNode> left_value = evalNode(table, row, filter.left.get());
-	std::unique_ptr<ValueNode> right_value = evalNode(table, row, filter.right.get());
+bool USql::evalRelationalOperator(const RelationalOperatorNode &filter, Table *table, Row &row) const {
+	std::unique_ptr<ValueNode> left_value = evalValueNode(table, row, filter.left.get());
+	std::unique_ptr<ValueNode> right_value = evalValueNode(table, row, filter.right.get());
 
 	double comparator;
 
 	if (left_value->node_type == NodeType::int_value && right_value->node_type == NodeType::int_value) {
 		comparator = left_value->getIntValue() - right_value->getIntValue();
-	} else if ((left_value->node_type == NodeType::int_value &&
-	right_value->node_type == NodeType::float_value) ||
-	(left_value->node_type == NodeType::float_value &&
-	right_value->node_type == NodeType::int_value) ||
-	(left_value->node_type == NodeType::float_value &&
-	right_value->node_type == NodeType::float_value)) {
+	} else if ((left_value->node_type == NodeType::int_value && right_value->node_type == NodeType::float_value) ||
+		(left_value->node_type == NodeType::float_value && right_value->node_type == NodeType::int_value) ||
+		(left_value->node_type == NodeType::float_value && right_value->node_type == NodeType::float_value)) {
 		comparator = left_value->getDoubleValue() - right_value->getDoubleValue();
-	} else if (left_value->node_type == NodeType::string_value ||
-	right_value->node_type == NodeType::string_value) {
+	} else if (left_value->node_type == NodeType::string_value || right_value->node_type == NodeType::string_value) {
 		comparator = left_value->getStringValue().compare(right_value->getStringValue());
 	} else {
 		// TODO throw exception
 	}
 
-
 	switch (filter.op) {
 		case RelationalOperatorType::equal:
 			return comparator == 0.0;
-			case RelationalOperatorType::not_equal:
-				return comparator != 0.0;
-				case RelationalOperatorType::greater:
-					return comparator > 0.0;
-					case RelationalOperatorType::greater_equal:
-						return comparator >= 0.0;
-						case RelationalOperatorType::lesser:
-							return comparator < 0.0;
-							case RelationalOperatorType::lesser_equal:
-								return comparator <= 0.0;
+		case RelationalOperatorType::not_equal:
+			return comparator != 0.0;
+		case RelationalOperatorType::greater:
+			return comparator > 0.0;
+		case RelationalOperatorType::greater_equal:
+			return comparator >= 0.0;
+		case RelationalOperatorType::lesser:
+			return comparator < 0.0;
+		case RelationalOperatorType::lesser_equal:
+			return comparator <= 0.0;
 	}
 
 	throw Exception("invalid relational operator");
-
 }
 
 
-std::unique_ptr<ValueNode>
-USql::evalNode(Table *table, std::vector<Row, std::allocator<Row>>::iterator &row, Node *node) const {
-	if (node->node_type == NodeType::database_value) {
-		DatabaseValueNode *dvl = static_cast<DatabaseValueNode *>(node);
-		ColDefNode col_def = table->get_column_def(
-			    dvl->col_name); // TODO optimize it to just get this def once
-			    auto db_value = row->ithColumn(col_def.order);
+std::unique_ptr<ValueNode> USql::evalValueNode(Table *table, Row &row, Node *node) {
+	if (node->node_type == NodeType::database_value || node->node_type == NodeType::column_name) {	// TODO sjednotit
+		return evalDatabaseValueNode(table, row, node);
 
-			    if (col_def.type == ColumnType::integer_type) {
-			    	return std::make_unique<IntValueNode>(db_value->integerValue());
-			    }
-			    if (col_def.type == ColumnType::float_type) {
-			    	return std::make_unique<FloatValueNode>(db_value->floatValue());
-			    }
-			    if (col_def.type == ColumnType::varchar_type) {
-			    	return std::make_unique<StringValueNode>(db_value->stringValue());
-			    }
+	} else if (node->node_type == NodeType::int_value || node->node_type == NodeType::float_value || node->node_type == NodeType::string_value) {
+		return evalLiteralValueNode(table, row, node);
 
-	} else if (node->node_type == NodeType::int_value) {
-		IntValueNode *ivl = static_cast<IntValueNode *>(node);
+	} else if (node->node_type == NodeType::function) {
+		return evalFunctionValueNode(table, row, node);
+	}
+	throw Exception("unsupported node type");
+}
+
+
+std::unique_ptr<ValueNode> USql::evalDatabaseValueNode(Table *table, Row &row, Node *node) {
+	auto *dvl = static_cast<DatabaseValueNode *>(node);
+	ColDefNode col_def = table->get_column_def( dvl->col_name); // TODO optimize it to just get this def once
+	auto db_value = row.ithColumn(col_def.order);
+
+	if (col_def.type == ColumnType::integer_type) {
+		return std::make_unique<IntValueNode>(db_value->getIntValue());
+	}
+	if (col_def.type == ColumnType::float_type) {
+		return std::make_unique<DoubleValueNode>(db_value->getDoubleValue());
+	}
+	if (col_def.type == ColumnType::varchar_type) {
+		return std::make_unique<StringValueNode>(db_value->getStringValue());
+	}
+	throw Exception("unknown database value type");
+}
+
+
+std::unique_ptr<ValueNode> USql::evalLiteralValueNode(Table *table, Row &row, Node *node) {
+	if (node->node_type == NodeType::int_value) {
+		auto *ivl = static_cast<IntValueNode *>(node);
 		return std::make_unique<IntValueNode>(ivl->value);
 
 	} else if (node->node_type == NodeType::float_value) {
-		FloatValueNode *ivl = static_cast<FloatValueNode *>(node);
-		return std::make_unique<FloatValueNode>(ivl->value);
+		auto *ivl = static_cast<DoubleValueNode *>(node);
+		return std::make_unique<DoubleValueNode>(ivl->value);
 
 	} else if (node->node_type == NodeType::string_value) {
-		StringValueNode *ivl = static_cast<StringValueNode *>(node);
+		auto *ivl = static_cast<StringValueNode *>(node);
 		return std::make_unique<StringValueNode>(ivl->value);
+
 	}
 
 	throw Exception("invalid type");
 }
 
 
-bool USql::evalLogicalOperator(LogicalOperatorNode &node, Table *pTable,
-			       std::vector<Row, std::allocator<Row>>::iterator &iter) const {
-	bool left = evalRelationalOperator(static_cast<const RelationalOperatorNode &>(*node.left), pTable, iter);
+std::unique_ptr<ValueNode> USql::evalFunctionValueNode(Table *table, Row &row, Node *node) {
+	auto  *fnc = static_cast<FunctionNode *>(node);
 
-	if ((node.op == LogicalOperatorType::and_operator && !left) ||
-	(node.op == LogicalOperatorType::or_operator && left))
+	std::vector<std::unique_ptr<ValueNode>> evaluatedPars;
+	for(auto & param : fnc->params) {
+		evaluatedPars.push_back(evalValueNode(table, row, param.get()));
+	}
+
+	// TODO use some enum
+	if (fnc->function == "lower") {
+		std::string str = evaluatedPars[0]->getStringValue();
+		std::transform(str.begin(), str.end(), str.begin(), [](unsigned char c) -> unsigned char { return std::tolower(c); });
+		return std::make_unique<StringValueNode>(str);
+	}
+	if (fnc->function == "upper") {
+		std::string str = evaluatedPars[0]->getStringValue();
+		std::transform(str.begin(), str.end(), str.begin(), [](unsigned char c) -> unsigned char { return std::toupper(c); });
+		return std::make_unique<StringValueNode>(str);
+	}
+
+	if (fnc->function == "to_date") {
+		std::string date = evaluatedPars[0]->getStringValue();
+		std::string format = evaluatedPars[1]->getStringValue();
+		long epoch_time = string_to_date(date, format);
+		return std::make_unique<IntValueNode>(epoch_time);
+	}
+	if (fnc->function == "to_string") {
+		long date = evaluatedPars[0]->getIntValue();
+		std::string format = evaluatedPars[1]->getStringValue();
+		std::string formated_date = date_to_string(date, format);
+		return std::make_unique<StringValueNode>(formated_date);
+	}
+
+	throw Exception("invalid function");
+}
+
+
+bool USql::evalLogicalOperator(LogicalOperatorNode &node, Table *pTable, Row &row) const {
+	bool left = evalRelationalOperator(static_cast<const RelationalOperatorNode &>(*node.left), pTable, row);
+
+	if ((node.op == LogicalOperatorType::and_operator && !left) || (node.op == LogicalOperatorType::or_operator && left))
 		return left;
 
-	bool right = evalRelationalOperator(static_cast<const RelationalOperatorNode &>(*node.right), pTable, iter);
+	bool right = evalRelationalOperator(static_cast<const RelationalOperatorNode &>(*node.right), pTable, row);
 	return right;
 }
 
 
-std::unique_ptr<ValueNode>
-USql::evalArithmetic(ColumnType outType, ArithmeticalOperatorNode &node, Table *table,
-		     std::vector<Row, std::allocator<Row>>::iterator &row) const {
+std::unique_ptr<ValueNode> USql::evalArithmeticOperator(ColumnType outType, ArithmeticalOperatorNode &node, Table *table, Row &row) const {
 	if (node.op == ArithmeticalOperatorType::copy_value) {
-		return evalNode(table, row, node.left.get());
+		return evalValueNode(table, row, node.left.get());
 	}
 
-	std::unique_ptr<ValueNode> left = evalNode(table, row, node.left.get());
-	std::unique_ptr<ValueNode> right = evalNode(table, row, node.right.get());
+	std::unique_ptr<ValueNode> left = evalValueNode(table, row, node.left.get());
+	std::unique_ptr<ValueNode> right = evalValueNode(table, row, node.right.get());
 
 	if (outType == ColumnType::float_type) {
 		double l = ((ValueNode *) left.get())->getDoubleValue();
 		double r = ((ValueNode *) right.get())->getDoubleValue();
 		switch (node.op) {
 			case ArithmeticalOperatorType::plus_operator:
-				return std::make_unique<FloatValueNode>(l + r);
-				case ArithmeticalOperatorType::minus_operator:
-					return std::make_unique<FloatValueNode>(l - r);
-					case ArithmeticalOperatorType::multiply_operator:
-						return std::make_unique<FloatValueNode>(l * r);
-						case ArithmeticalOperatorType::divide_operator:
-							return std::make_unique<FloatValueNode>(l / r);
-							default:
-								throw Exception("implement me!!");
+				return std::make_unique<DoubleValueNode>(l + r);
+			case ArithmeticalOperatorType::minus_operator:
+				return std::make_unique<DoubleValueNode>(l - r);
+			case ArithmeticalOperatorType::multiply_operator:
+				return std::make_unique<DoubleValueNode>(l * r);
+			case ArithmeticalOperatorType::divide_operator:
+				return std::make_unique<DoubleValueNode>(l / r);
+			default:
+				throw Exception("implement me!!");
 		}
 	} else if (outType == ColumnType::integer_type) {
-		int l = ((ValueNode *) left.get())->getIntValue();
-		int r = ((ValueNode *) right.get())->getIntValue();
+		long l = ((ValueNode *) left.get())->getIntValue();
+		long r = ((ValueNode *) right.get())->getIntValue();
 		switch (node.op) {
 			case ArithmeticalOperatorType::plus_operator:
 				return std::make_unique<IntValueNode>(l + r);
-				case ArithmeticalOperatorType::minus_operator:
-					return std::make_unique<IntValueNode>(l - r);
-					case ArithmeticalOperatorType::multiply_operator:
-						return std::make_unique<IntValueNode>(l * r);
-						case ArithmeticalOperatorType::divide_operator:
-							return std::make_unique<IntValueNode>(l / r);
-							default:
-								throw Exception("implement me!!");
+			case ArithmeticalOperatorType::minus_operator:
+				return std::make_unique<IntValueNode>(l - r);
+			case ArithmeticalOperatorType::multiply_operator:
+				return std::make_unique<IntValueNode>(l * r);
+			case ArithmeticalOperatorType::divide_operator:
+				return std::make_unique<IntValueNode>(l / r);
+			default:
+				throw Exception("implement me!!");
 		}
 
 	} else if (outType == ColumnType::varchar_type) {
@@ -380,9 +488,8 @@ USql::evalArithmetic(ColumnType outType, ArithmeticalOperatorNode &node, Table *
 		switch (node.op) {
 			case ArithmeticalOperatorType::plus_operator:
 				return std::make_unique<StringValueNode>(l + r);
-
-				default:
-					throw Exception("implement me!!");
+			default:
+				throw Exception("implement me!!");
 		}
 	}
 
@@ -390,19 +497,7 @@ USql::evalArithmetic(ColumnType outType, ArithmeticalOperatorNode &node, Table *
 }
 
 
-
-Table *USql::find_table(const std::string name) {
-	auto name_cmp = [name](const Table& t) { return t.m_name == name; };
-	auto table_def = std::find_if(begin(m_tables), end(m_tables), name_cmp);
-	if (table_def != std::end(m_tables)) {
-		return table_def.operator->();
-	} else {
-		throw Exception("table not found (" + name + ")");
-	}
-}
-
-
-std::unique_ptr<Table> USql::create_stmt_result_table(int code, std::string text) {
+std::unique_ptr<Table> USql::create_stmt_result_table(long code, const std::string& text) {
 	std::vector<ColDefNode> result_tbl_col_defs{};
 	result_tbl_col_defs.push_back(ColDefNode("code", ColumnType::integer_type, 0, 1, false));
 	result_tbl_col_defs.push_back(ColDefNode("desc", ColumnType::varchar_type, 1, 255, false));
@@ -417,4 +512,16 @@ std::unique_ptr<Table> USql::create_stmt_result_table(int code, std::string text
 	return std::move(table_def);
 }
 
+
+
+Table *USql::find_table(const std::string &name) {
+	auto name_cmp = [name](const Table& t) { return t.m_name == name; };
+	auto table_def = std::find_if(begin(m_tables), end(m_tables), name_cmp);
+	if (table_def != std::end(m_tables)) {
+		return table_def.operator->();
+	} else {
+		throw Exception("table not found (" + name + ")");
+	}
 }
+
+}	// namespace

usql/usql.h

@@ -4,13 +4,15 @@
 #include "table.h"
 
 #include <string>
+#include <list>
 
 namespace usql {
 
 class USql {
 
 public:
-    USql() {};
+    USql() = default;
+
 
     std::unique_ptr<Table> execute(const std::string &command);
 
@@ -18,41 +20,37 @@ private:
     std::unique_ptr<Table> execute(Node &node);
 
     std::unique_ptr<Table> execute_create_table(CreateTableNode &node);
-
+    std::unique_ptr<Table> execute_create_table_as_table(CreateTableAsSelectNode &node);
     std::unique_ptr<Table> execute_insert_into_table(InsertIntoTableNode &node);
-
     std::unique_ptr<Table> execute_select(SelectFromTableNode &node);
-
     std::unique_ptr<Table> execute_delete(DeleteFromTableNode &node);
-
     std::unique_ptr<Table> execute_update(UpdateTableNode &node);
-
     std::unique_ptr<Table> execute_load(LoadIntoTableNode &node);
-
-    Table *find_table(const std::string name);
-
-    std::unique_ptr<Table> create_stmt_result_table(int code, std::string text);
+    std::unique_ptr<Table> execute_save(SaveTableNode &node);
 
 
 private:
-    bool evalWhere(Node *where, Table *table,
-		   std::vector<Row, std::allocator<Row>>::iterator &row) const;
+    bool evalWhere(Node *where, Table *table, Row &row) const;
 
-    std::unique_ptr<ValueNode> evalNode(Table *table, std::vector<Row, std::allocator<Row>>::iterator &row,
-					Node *node) const;
+    static std::unique_ptr<ValueNode> evalValueNode(Table *table, Row &row, Node *node);
+    static std::unique_ptr<ValueNode> evalDatabaseValueNode(Table *table, Row &row, Node *node);
+    static std::unique_ptr<ValueNode> evalLiteralValueNode(Table *table, Row &row, Node *node);
+    static std::unique_ptr<ValueNode> evalFunctionValueNode(Table *table, Row &row, Node *node);
 
-    bool evalRelationalOperator(const RelationalOperatorNode &filter, Table *table,
-				std::vector<Row, std::allocator<Row>>::iterator &row) const;
 
-    bool evalLogicalOperator(LogicalOperatorNode &node, Table *pTable,
-			     std::vector<Row, std::allocator<Row>>::iterator &iter) const;
+    bool evalRelationalOperator(const RelationalOperatorNode &filter, Table *table, Row &row) const;
+    bool evalLogicalOperator(LogicalOperatorNode &node, Table *pTable, Row &row) const;
+    std::unique_ptr<ValueNode> evalArithmeticOperator(ColumnType outType, ArithmeticalOperatorNode &node, Table *table, Row &row) const;
+
+
+    static std::unique_ptr<Table> create_stmt_result_table(long code, const std::string& text);
+    static std::tuple<int, ColDefNode> getColumnDefinition(Table *table, SelectColNode *select_col_node, int col_order) ;
+    Table *find_table(const std::string &name);
 
-    std::unique_ptr<ValueNode> evalArithmetic(ColumnType outType, ArithmeticalOperatorNode &node, Table *table,
-					      std::vector<Row, std::allocator<Row>>::iterator &row) const;
 
 private:
     Parser m_parser;
-    std::vector<Table> m_tables;
+    std::list<Table> m_tables;
 };
 
-}
+}	// namespace

utils/local_install.sh

@@ -1,7 +1,7 @@
 #!/bin/sh
 
 gcc -std=c99 -c -O2 -o linenoise.o clib/linenoise.c
-c++ -c -O2  -I/usr/local/opt/openssl/include -Iclib --std=c++17  ml.cpp ml_io.cpp ml_date.cpp ml_string.cpp ml_util.cpp ml_profiler.cpp clib/json11.cpp clib/csvparser.cpp clib/sslclient.cpp clib/printf.cpp
+c++ -c -O2  -I/usr/local/opt/openssl/include -Iclib --std=c++17  ml.cpp ml_io.cpp ml_date.cpp ml_string.cpp ml_util.cpp ml_profiler.cpp ml_usql.cpp clib/json11.cpp clib/csvparser.cpp clib/sslclient.cpp clib/printf.cpp usql/exception.cpp usql/lexer.cpp usql/parser.cpp usql/usql.cpp usql/table.cpp usql/table.h usql/row.cpp usql/csvreader.cpp usql/usql.cpp
 c++ -o ml -O2 -L/usr/local/lib -L/usr/local/opt/openssl/lib -lm -lstdc++ -lcrypto -lssl *.o
 
 cp stdlib/*.lsp /usr/local/var/mlisp/

utils/remote_install.sh

@@ -24,7 +24,7 @@ fi
 
 echo "Building ml"
 ssh -p 5333 root@46.28.109.184 "cd /tmp/mlisp; gcc -std=c99 -c -O2 -o linenoise.o clib/linenoise.c"
-ssh -p 5333 root@46.28.109.184 "cd /tmp/mlisp; c++ -c -O2  -I/usr/local/opt/openssl/include -Iclib --std=c++17  ml.cpp ml_io.cpp ml_date.cpp ml_string.cpp ml_util.cpp ml_profiler.cpp clib/json11.cpp clib/csvparser.cpp clib/sslclient.cpp clib/printf.cpp"
+ssh -p 5333 root@46.28.109.184 "cd /tmp/mlisp; c++ -c -O2  -I/usr/local/opt/openssl/include -Iclib --std=c++17  ml.cpp ml_io.cpp ml_date.cpp ml_string.cpp ml_util.cpp ml_profiler.cpp ml_usql.cpp  clib/json11.cpp clib/csvparser.cpp clib/sslclient.cpp clib/printf.cpp usql/exception.cpp usql/lexer.cpp usql/parser.cpp usql/usql.cpp usql/table.cpp usql/table.h usql/row.cpp usql/csvreader.cpp usql/usql.cpp"
 ssh -p 5333 root@46.28.109.184 "cd /tmp/mlisp; c++ -o ml -O2 -L/usr/local/lib -L/usr/local/opt/openssl/lib -lm -lstdc++ -lcrypto -lssl *.o"